• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.29-34
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• 2011

Various types of coastal structures have been constructed to prevent coastal disasters. Among these coastal structures, submerged breakwaters have been used more widely than all of the other coastal structures because of their excellent advantages in scenery effects, construction efficiency, and environmental benefits. This study investigated the potential of the horizontal plate submerged breakwater model. Usually, it is necessary for a submerged breakwater to minimize and compensate for the negative impacts on the marine environment and ecosystem caused by the marine construction. Thus, the prevention of coastal disasters was verified for this submerged breakwater model, regardless of its function as a fish reef. The purpose of this study was to investigate the hydraulic characteristics with changes in the crest width and porosity of a horizontal plate submerged breakwater and compare the results of this study with the results of other studies on permeable and impermeable submerged breakwaters.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.352-359
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• 2005

In this study, seismic refraction survey and MASW at dam crest and down-hole test and cross hole test in the boring holes located in dam crest through the core are performed to fin out dynamic material properties, are needed to evaluate dynamic safety of rockfill dam using dynamic analysis method. From the field test and geophysical exploration, applied such as above, p-wave and s-wave velocity profile of each layer of dam body. Dynamic material properties, such as elastic modulus, shear modulus, poissong's ration, are obtained from p-wave and s-wave velocity profile and density profile from formation density logging test.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.462-465
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• 2011

본 논문에서는 다중 반송파, 특히 OFDM 시스템의 PAPR 을 감소시킬 수 있는 CFR 알고리즘을 다룬다. 기존의 피크 윈도윙 기법이 윈도우 길이 내에 피크들이 여러 개 있을 경우, 과도 clipping 으로 인하여 성능이 열화되는 현상을 개선하기 위하여 포락선 기반 피크 윈도윙 기법을 적용한다. 뿐만 아니라, 피크 윈도윙이 가지고 있는 EVM 열화를 완화하기 위하여 기존의 단순 clipping 기법과 혼합하여 시스템에서 요구하는 EVM 성능뿐 아니라 ACLR 성능까지도 만족하도록 한다. MATLAB 을 이용하여 알고리즘을 검증하고, 하드웨어 구현을 위하여 Xilinx Virtex5 를 이용하여 검증하여 제안하는 기법의 복잡도는 높지만 EVM 과 ACLR 성능이 우수함을 알 수 있다. 효율적인 주파수 이용과 수신 성능 측면에서 우수한 성능을 보인다. 따라서 DVB-T 나 LTE, IEEE 802.16m 등의 차세대 방송 및 통신의 전송에 이용되는 OFDM 신호의 PAPR 을 효과적으로 줄일 수 있는 기법으로 적용될 수 있다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.3
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• pp.2716-2725
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• 1972

Side channel spillways based on Hinds theory were tested. Surface water level at the beginning point of side channel is the same as the crest level of weir in the usual design. Here, side channel section were moved upwards $\frac{1}{2}$ of the total head on the crest and test(revised experiment) were made. In the revised experiments, coefficients of discharge for design flood (Q) were the same with that of original design experiments. In case of 1.2Q a little influence of submergence were appeared, coefficients of discharge were decreased to be about 97.6% of that of original design experiments, therefore, Reservoir flood water level become higher about 2-3cm than original case. So revised design can be used for actual purpose and it will brings much savings in construction cost of side channel spillway.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.223-228
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• 2000

The current slope stability analysis of a filldam is based on the limit equilibrium method, and in calculation of safety factor during earthquake, adopts the seismic intensity method in which it considers a uniform seismic force from dam foundation to crest. However the observed behaviour of filldam during earthquake shows some different behaviour in that at the crest the measured acceleration is usually several times the ground acceleration. In this study, slope stability calculations of a filldam are provided based on the modified seismic intensity method, which can take into account the amplification phenomena of acceleration in the upper part of dam. And also the results of calculations are compared with that of current seismic intensity method.

• Journal of Ocean Engineering and Technology
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• v.21 no.6
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• pp.47-52
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• 2007

This paper presents the design of a submerged breakwater, which functions as an eco-structure in a marine environment. Newly patented blocks were used in the submerged breakwater to both make it stable and provide an inhabitable space for fish. To investigate the wave transmission of the proposed submerged breakwater, parametric studies were conducted through two-dimensional hydraulic tests, which were carried out at the National Fisheries Research and Development Institute (NFRDI) in South Korea. Those parameters are relative crest width (B/L), wave steepness (H/L), relative crest depth (hB/H), and submerged breakwater configuration. The hydraulic experimental results can be used to predict the performance of the proposed submerged breakwater covered with the multi-function blocks.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.356-360
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• 2005

Xanthine dehydrogenase (XDH), a classic enzyme involved in purine catabolism, can catalyze the formation of redox-signaling reactive oxygen and nitrogen species such as superoxide and nitric oxide. We generated transgenic plants of Arabidopsis in which XDH was knocked out by introduction of hairpin RNA-expression vector. Expression analysis by reverse transcription-PCR and in-gel staining of XDH activity revealed that transgenic lines efficiently suppressedXDH expression at the transcriptional level, demonstrating that RNA interference was successfully induced. XDH-suppressed transgenic lines exhibitedincreased biomass production during the growth of seedlings.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.49-56
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• 1999

This paper present a study on the application of sound pressure and vibration signals to detect the presence of defects in a rolling element bearing using a statistical analysis method. The well established statistical parameters such as the crest factor and the distribution of moments including kurtosis and skewless are utilized in this study. In addition, other statistical parameters derived from the beta distribution function are also used. A comparison study on the performance of the different types of parameter used is also performed. The statistical analysis is used because of its simplicity and quick computation. Under ideal conditions, the statistical method can be used to identify the different types of defect present in the bearing. In addition, the results also reveal that there is no significant advantages in using the beta function parameters when compared to using kurtosis and the crest factor for detecting and identifying defects in rolling element bearings from both sound and vibration signals.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.746-749
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• 2002

This paper presents a new control method for the high frequency electronic ballast which is operated with raw rectified dc link using diode bridge. For the commercial electronic ballast, proper ac input power factor and crest factor of the lamp current are required. The most ballast, therefore, has a active or passive power factor collection (PFC) circuit. With the proposed method, it can be achieved simultaneously that grater than 0.9 of input power factor and less than 1.85 of lamp current crest factor without any PFC circuit. In this paper, the proposed ballast control scheme and the experimental results for the application to the fluorescent lamp are described.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.120-122
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• 2012

기존 소프트웨어 테스팅 기법은 개발자가 수동으로 테스트 케이스를 작성해야 하는 비효율성으로 인해 임베디드 소프트웨어의 안정성 확보에 어려움이 있다. Concolic 테스팅 기법은 자동으로 소프트웨어 테스트 케이스를 생성함으로써 기존 소프트웨어 테스팅 기법의 문제를 해결했지만, 임베디드 소프트웨어 테스트에 필수적인 bitwise 연산을 지원하지 않는 등의 문제가 있었다. 본 논문에서는 임베디드 소프트웨어를 위해 bitwise 연산을 지원하는 Concolic 테스팅 개선 방법에 대한 연구를 수행하고 오픈 소스 임베디드 소프트웨어 Busybox에 적용하여 기존 연구와 결과를 비교하였다. Busybox의 10개 유틸리티에 적용한 결과 기존 연구 결과 대비 평균 33%의 분기 커버리지 향상이 있었다.